Original Story by Dr Glenn Green, Benedict of Ann Arbor, University of Michigan, Victoria, Australia, 3Ders.org

Life-saving, 3D-printed custom splint steps closer to market

An adolescent girl has been given 3D printed tracheal splints to treat a congenital breathing condition called tracheobronchomalacia (TBM). Staff at the University of Michigan used an EOS 3D printer and a biomaterial called Polycaprolactone (PCL) to make the splints.

TBM, a rare condition characterized by flaccidity of the tracheal support, is becoming easier to treat thanks to the work of medical professionals and 3D printing technology. Prior to the surgery on the unnamed adolescent girl, 3D printed splints had been used to treat TBM in the cases of three baby boys and a baby girl, each of whom had their collapsed airways reopened with the 3D printed splints. Dr Glenn Green, a pediatric otolaryngologist from CS Mott Children's Hospital in Ann Arbor, joined forces with Dr Scott Hollister, a professor of biomedical engineering and lead researcher at the University of Michigan, to perform the revolutionary surgery on the girl.

Green believes that, despite its rarity, TBM deserves scientific attention in order to improve the lives of sufferers: ?Even if a market is relatively small, it doesn?t diminish the human need to be treated,? he said. ?It is estimated that one in every 2,000 children worldwide is affected by this life-threatening condition. When I started designing my own porous scaffolds for anatomic reconstruction, I realized that 3D printing would be ideal for creating the complex geometries I had in mind. It is now pretty automatic to generate an individualized splint design and print it; the whole process only takes about two days now instead of three to five.?

When 3D printing objects that will be used in and around the human body, it is important to choose the right printing materials, the level of toxicity in many common printing materials being far too high for medical use. In this case, the surgical team decided to use Polycaprolactone (PCL) for their 3D printed tracheal splints. The material has a long resorption time, which is important because the splints need to last for around two years. It is also ductile and therefore unlikely to damage bodily tissue if it moves out of place.

To create a properly fitting tracheal splint for the patient, the medical team first had to obtain MRI and CT scans to build up an accurate 3D model of her anatomy. Using this data, the team was able to 3D print a tailor-made splint for the girl, designed with a highly compliant, porous structure of interconnected spaces that can expand as the airway matures. The girl?s splint-supported trachea then got to work straight after the operation.

Dr Hollister and his colleagues from the University of Michigan used an EOS FORMIGA P 100 3D printer to 3D print the tracheal scaffolds. The printer has been in the university?s possession since 2006, and has been used to aid research into scaffolds and biomaterials. ?I chose EOS because we were looking for a system that was flexible and allowed us to change parameter settings such as laser power, speed, powder bed temperature and so on, which we needed to do to customize our builds,? Hollister explained.

Hollister hopes that 3D printing within the medical world will continue to grow, enabling more patients to breathe easy when difficulties arise. ?I see a time soon, probably within the next five years, when many hospitals and medical centers will print their own devices specifically for their own patients and not need to get them off the shelf,? said Hollister. ?If we can expand the number of biomaterials used in additive manufacturing, we can tackle a tremendous number of problems in all fields of reconstructive surgery and make enormous strides for the benefit of patients.?